Compressing Black Powder

yonderin

yonderin

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Who loads black powder cartridge and what is your opinion/findings on compressing the loads?

I've read of GI .45/70 loads being compressed by as much as .3 inch. In order to get 60 gr into a case to push a 500+ gr bullet that will still chamber, it appears I'll need to compress it by about a quarter inch, even using a drop tube.

From what I've read it shouldn't be a concern but feedback/education from anybody currently doing it would be appreciated.
 
Quarter inch compression is a little much. BP should have slight compression. Not important how much powder. I compress mine about a sixteenth of an inch with a 0.030 wax under the bullet. Lube used is SPG. BP. Bullets should be of softer lead 50% w-w and
50% pure lead. Hard bullets will cause leading. BP shooting is try it and see what works in your gun. My original trapdoor shoots well with 55 grs of Old enysford and 500 gr Lee.
 
It's not a problem at all. Most of my loads use compression of between 0.050" and 0.250". I generally don't over that.

BTW, sometimes you'll hear people say that Swiss doesn't like to be compressed but that is not at all true. It can work very well, although it does work quite well with only minimal compression too.

Chris.
 
I compress the living Jebus out of my loads. Eg, 70 gr 2F Goex under a 535 grain Lyman Postell. Can't recall how much compression that is, but it's a lot. I started at 50 gr and accuracy steadily improved as charge weight and compression increased. Goex is supposed to like significant compression, and that's been my experience. I'm using straight WW lubed with SPG in the grooves only. Zero leading and outstanding accuracy. I would just work up a load as for smokeless, going in 5 grain increments. 70 gr is about all you can get in a .45-70 case with a 535 postell seated to the front driving band... ymmv depending on your bullet and how far you can seat out.

I don't care about the compression, I care about the performance. I wouldn't worry in the slightest about how much I'm squeezing the load except for what the target and chronograph tell me.
 
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The main thing is you need to use a compression plug mounted in your expander die body. Don’t use the bullet to compress the BP.
I have no problem compressing 36 gr. of 2fg GOEX in 45 Colt Starline cases with a 260 gr. (LEE mold 45-255-RF-DC) bullet.
 
I find black powder loads NEED to be compressed for consistent performance. If I can't get a compressed load with fff or ff I go to f.

Likely other black powder shooters have found the same thing.

When I first started loading muzzle loaders I had accuracy issues for two reasons. One was undersized patching material and the other was inconsistent tamping of the patched ball over the powder.

An old timer took me under his wing and taught me about the Joys of Patching correctly. Most people use undersized patches. Proper patch lube helps a bit. It's difficult to find consistent patch material, I have a supply of church linen which runs a consistent .015 inches. The bore on my 50cal, Lyman Plains Rifle is a tad on the large side. I had to order a .500 round ball mold and .523 maxi mold to get it to shoot well.

My reasoning was that if consistent tamping of the ball onto the powder charge works for muzzle loaders it should work for black powder cartridges as well.

I compress the load with the bullet as I seat it. Contrary to the advice given above. I've quite literally shot thousands of 40-60 and 45-70 black powder cartridges loaded this way without an issue and long brass life. I also had a 45 colt made on a small Martini action that used a take off barrel from a bin that was obviously a black powder barrel and was marked as a Marlin. It liked the compressed loads as well but really preferred hollow base bullets, filled with Bondo.
 
Loaded them up and set them off with no apparent issues. I wasn't particularly concerned from what I'd read but before I buggered up a really nice repro Sharps, figgered I'd see what current shooters were doing. Never compressed loads that much before.

Horrible accuracy, convinced it's a problem with the paper patching. Sized and patched them the same as Lee 405 gr hollow base bullets I've cast which shot much better although they didn't group as well as I'd like.
 
Do you know the diameter of your bore????

Cast bullets usually shoot best when they are a few thousandths oversize. Paper patching should take up the difference but even then, they need to be tight in the bore.

PM Jethunter on this. That fellow has forgotten more than most people know when it comes to shooting cast bullets.
 
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